I really like this chapter. This is Kubo at some of his finest, imo.
Unohana reveals through an inner monologue that even thought she's infamously the the strongest Kenpachi, Zaraki is still stronger than her.
Kubo also tied it in nicely with previous parts of the the manga.
Zaraki seems at first glance to just be a simple, battle loving brute, but in reality he's a deeper character than that.

Zaraki's odd visions from the previous chapter are explained.
Unoahana is killing him and then reviving him, which explains Zaraki's lose of consciousness.
Each time he's revived, Zaraki is getting a bit stronger and more deadly.
I wonder if Kyoraku knew that this is what Unohana was going to do...

The revelation about Kenpachi's true strength kind of reminds me Orihime and Ulquiorra.
Please keep up the good work Kubo!